1. Field of the Invention
The present invention relates to a heat exchanger that uses water liquid and vapor phases transformation to enhance heat exchange performance thereby to save energy and reduce thermal pollution.
2. Description of the Prior Art
A conventional refrigeration air conditioning system 9 (as shown in FIG. 1) mainly includes a compressor 91, a condenser 92, an evaporator 93, a refrigerant flow controller 94 and a refrigerant switch valve 95. The condenser 92 and the evaporator 93 generally are called heat exchanger (or heat exchange device) A. It mainly includes a coiled tube L and an air fan motor M (referring to FIG. 2). Such a heat exchanger has drawbacks in operation, notably:                1. During heat discharge operation, heat exchange occurs between air intake and the coiled tube of the heat exchanger. Heated air is directly discharged into atmosphere. The heated air produces thermal pollution to the environment.        2. In the lower temperature seasons (such as winter) water content in the air is low during heat absorption operation. Only sensible heat is exchanged during heat exchange process. As a result, heat exchange performance and efficiency decrease significantly.        